U.S. patent number 4,298,105 [Application Number 06/094,692] was granted by the patent office on 1981-11-03 for control valve mechanism for a power transmission.
This patent grant is currently assigned to General Motors Corporation. Invention is credited to Michael L. Duhaime.
United States Patent |
4,298,105 |
Duhaime |
November 3, 1981 |
Control valve mechanism for a power transmission
Abstract
An electro-hydraulic control for a power transmission has a
solenoid controlled shift valve and a hydraulic controlled shift
valve. Preferably, the solenoid controlled valve controls the
control clutch while the hydraulic controlled valve controls the
clutch or brake which is effective to establish a drive ratio in
the transmission. When a ratio change involving the disengagement
of the clutch or brake occurs, the exhaust fluid therefrom operates
on an electrical switch which is effective to provide momentary
disengagement of the torque converter clutch.
Inventors: |
Duhaime; Michael L. (Detroit,
MI) |
Assignee: |
General Motors Corporation
(Detroit, MI)
|
Family
ID: |
22246617 |
Appl.
No.: |
06/094,692 |
Filed: |
November 16, 1979 |
Current U.S.
Class: |
192/3.23;
192/3.24; 192/3.27; 192/3.31; 477/63 |
Current CPC
Class: |
F16H
47/08 (20130101); F16H 61/143 (20130101); Y10T
477/6351 (20150115) |
Current International
Class: |
F16H
47/00 (20060101); F16H 47/08 (20060101); F16H
61/14 (20060101); B60K 041/24 () |
Field of
Search: |
;192/3.23,3.24,3.25,3.26,3.3,3.32,3.57,4A,12C,13R,87.13,87.12,87.11,3.27,3.31
;74/752A,752C,868 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Krizmanich; George H.
Attorney, Agent or Firm: Scherer; Donald F.
Claims
The embodiments of the invention in which an exclusive property or
privilege is claimed are defined as follows:
1. A control valve for use in a power transmission having a pair of
friction drive establishing means, one of which drive establishing
means is controlled by an electrically-operated solenoid valve and
the other of which drive establishing means is controlled by a
hydraulically-operated shift valve, said control valve comprising;
a stepped valve bore, a differential area spool valve slidably
disposed in the stepped valve bore and a passage means
interconnecting the hydraulic shift valve and the differential area
of said valve spool, a restricted exhaust being interconnected with
said passage means; and electrical switch means connected in said
passage means upstream of said restricted exhaust and being
pressure-activated to assume an actuated position to control the
solenoid valve to disengage said one drive establishing means, said
passage means being operable to provide a controlled pressure
outlet in cooperation with said valve spool and said restricted
exhaust for said other drive establishing means such that on
disengagement of said other drive establishing means the pressure
within said passage means is initially increased sufficiently to
actuate said switch means and after a predetermined time the
pressure therein is reduced through said restricted exhaust to
permit said switch means to return to its unactuated condition.
2. A control valve structure for use in a power transmission having
a pair of friction clutch means, one of which clutch means is
controlled by an electrically-operated solenoid valve and the other
of which clutch means is controlled by a hydraulically-operated
shift valve, said control valve structure comprising; a stepped
valve bore, a differential area spool valve slidably disposed in
the stepped valve bore and a passage means interconnecting the
hydraulic shift valve and the differential area of said valve
spool, a restricted exhaust being interconnected with said passage
means; and electrical switch means connected in said passage means
upstream of said restricted exhaust and being pressure-activated to
assume an actuated postion to control the solenoid valve to
disengage said one clutch means, said passage means being operable
to provide a controlled pressure outlet in cooperation with said
valve spool and said restricted exhaust for said other clutch means
such that on disengagement of said other clutch means the pressure
within said passage means is initially increased sufficiently to
actuate said switch means and after a predetermined time the
pressure therein is reduced through said restricted exhaust to
permit said switch means to return to its unactuated condition.
3. A control valve structure for use in a power transmission having
a friction clutch means and a friction brake means, said clutch
means being controlled by an electrically-operated solenoid valve
and said brake means being controlled by a hydraulically-operated
shift valve, said control valve structure comprising; a stepped
valve bore, a differential area spool valve slidably disposed in
the stepped valve bore and a passage means interconnecting the
hydraulic shift valve and the differential area of said valve
spool, a restricted exhaust being interconnected with said passage
means; and electrical switch means connected in said passage means
upstream of said restricted exhaust and being pressure-activated to
assume an actuated position to control the solenoid valve to
disengage said clutch means, said passage means being operable to
provide a controlled pressure outlet in cooperation with said valve
spool and said restricted exhaust for said brake means such that on
disengagement of said other brake means the pressure within said
passage means is initially increased sufficiently to actuate said
switch means and after a predetermined time the pressure therein is
reduced through said restricted exhaust to permit said switch means
to return to its unactuated condition.
4. A control valve structure for use in a power transmission having
torque converter clutch means and a drive ratio establishing means,
said torque converter clutch means being controlled by an
electrically-operated solenoid valve and the drive ratio
establishing means being controlled by a hydraulically-operated
shift valve, said control valve structure comprising; a stepped
valve bore, a differential area spool valve slidably disposed in
the stepped valve bore and a passage means interconecting the
hydraulic shift valve and the differential area of said valve
spool, a restricted exhaust being interconnected with said passage
means; and electrical switch means connected in said passage means
upstream of said restricted exhaust and being pressure-activated to
assume an actuated position to control the solenoid valve to
disengage said torque converter clutch means, said passage means
being operable to provide a controlled pressure outlet in
cooperation with said valve spool and said restricted exhaust for
said drive ratio establishing means such that on disengagement of
said drive ratio establishing means the pressure within said
passage means is initially increased sufficiently to actuate said
switch means and after a predetermined time the pressure therein is
reduced through said restricted exhaust to permit said switch means
to return to its unactuated condition.
Description
This invention relates to control mechanisms and more particularly
to hydraulic control mechanisms for automatic transmissions.
In an effort to provide improved transmission efficiency and
thereby increase fuel mileage for vehicles, it is proposed to
provide a torque converter clutch which will be effective to
directly couple the input and output members of a torque converter
or fluid coupling thereby eliminating the inefficiency of this
hydraulic device. It is considered that the torque converter clutch
must be engaged for more than one gear ratio to obtain maximum
benefit from such a device. Accordingly, in a four-speed
transmission, the torque converter clutch would be engaged at least
in the third and fourth gear ratios and preferably in the second,
third and fourth gear ratios.
When a downshift from the highest ratio to an underlying ratio
occurs, it is desirable to momentarily disengage the torque
converter clutch during the ratio change to permit the shift energy
to be accommodated by the torque converter rather than by a
positive drive connection such as a clutch.
The present invention will permit such a sequence of events to
occur during a downshift in a transmission incorporating a torque
converter clutch. The same or similar control systems can be
utilized in any power transmission wherein it is desirable to
momentarily disengage a drive establishing device such as a clutch
or brake during a ratio interchange and to subsequently reengage
the device upon completion of the ratio change.
It is therefore an object of this invention to provide an improved
control valve mechanism for a power transmission wherein a friction
drive establishing device is momentarily disengaged during a ratio
change and reengaged after the ratio change.
It is another object of this invention to provide an improved
control valve mechanism for a power transmission wherein a clutch
member is controlled by a solenoid valve to be momentarily
disengaged in response to a disengagement of another clutch or
brake within the drive system when the other clutch or brake is
disengaged to effect a ratio change within the transmission.
A further object of this invention is to provide an improved valve
control mechanism for a power transmission wherein a solenoid
controlling a torque converter clutch is actuated in response to
the exhausting of a ratio drive establishing device to momentarily
disengage the torque converter clutch during a ratio change
involving the drive establishing device.
Another object of this invention is to provide an improved control
valve mechanism for a power transmission wherein a solenoid
controlled torque converter clutch is momentarily disengaged during
a ratio interchange in the power transmission by controlling the
exhaust pressure of an off-going friction device in such a manner
as to actuate a pressure responsive electrical switch which
controls the solenoid to momentarily disengage the torque converter
clutch during the ratio interchange.
These and other objects and advantages of the present invention
will be more apparent from the following description and drawings
in which:
FIG. 1 is a diagrammatic representation of a control system
utilizing the present invention; and
FIG. 2 is a diagrammatic representation of a brake structure
replacing the clutch structure shown in FIG. 1.
Referring to the drawings, there is shown a conventional gear pump
10 which is driven, in a conventional manner by a conventional
torque converter 12 to supply high pressure fluid to a hydraulic
control system. The pump 10 takes fluid from a reservoir 14 through
a passage 16 and delivers the fluid at a high pressure to passage
18. The maximum fluid pressure in passage 18 is established by a
conventional pressure regulator valve 20 which exhausts excess
fluid into passage 16. The passage 18 is connected to a solenoid
valve 22, a governor valve 24, a throttle valve 26 and a manual
control valve 28. The solenoid valve 22 is a conventional solenoid
valve which is operative to selectively supply fluid pressure from
passage 18 to either fluid passage 30 or 32 depending on the
electrical condition of the solenoid. Both the passages 30 and 32
are connected to the torque converter 12. The passages, when not
pressurized, are connected to exhaust.
The torque converter 12 has an impeller 34 which is driven by an
input shell 36 and a turbine 38 which is effective to drive a
planetary gearing in a transmission, not shown, in a conventional
manner. The use of drive connections between torque converters and
planetary gearing arrangements is well-known and, for the purposes
of the present invention, the drive connection as shown in U.S.
Pat. No. 3,724,292 issued to Borman on Apr. 3, 1973, or U.S. Pat.
No. 3,321,056 issued to Winchell et al on May 23, 1967, is
considered illustrative.
Also incorporated within the torque converter 12 is a torque
converter clutch 40 which may be constructed in accordance with the
torque converter clutch as shown in U.S. Pat. No. 3,252,352 issued
to General et al on May 24, 1966. The fluid passage 30 is
selectively connected to deliver fluid to the torque converter 12
in such a manner as to engage the torque converter clutch 40; and
the fluid passage 32 is connected to direct fluid to the torque
converter 12 in such a manner as to disengage the torque converter
clutch 40. Such fluid connections are shown in the above-mentioned
General et al patent and similar control systems can be seen in
U.S. Pat. No. 3,730,315 issued to Annis et al on May 1, 1973, and
U.S. Pat. No. 3,693,478 issued to Malloy on Sept. 26, 1972.
The governor valve 24 may be constructed in accordance with that
shown in U.S. Pat. No. 3,559,667 issued to Koivunen on Feb. 2,
1971, or in accordance with any of the well-known governor valve
structures. The throttle valve 26 may be constructed in accordance
with any of the well-known throttle valves or in accordance with
that shown in U.S. Pat. No. 3,893,472 issued to Schuster on July 8,
1975. The governor valve 24 generates a pressure signal, in
proportion to vehicle speed, which is delivered to a fluid passage
44. The passage 44 is connected to a conventional shift valve 46
which may be constructed in accordance with the three-four shift
valve shown in U.S. Pat. No. 3,724,292. The throttle valve 26
generates a pressure signal, proportional to throttle position,
which is delivered through passage 48 to the shift valve 46.
The manual valve 28 may be constructed in accordance with any of
the well-known hydraulic manual valves utilized in power
transmissions. The manual valve 28 is effective to distribute
pressure from passage 18 to either a passage 50, which is connected
to the shift valve 46 are a passage 52, which is connected to a
control valve 54, depending upon the drive ratio selected by the
operator. If an automatic drive sequence is selected by the
operator, passage 50 will be pressurized and passage 52 will be
exhausted. If a drive range less than automatic (for example, the
low or intermediate ratio in a three-speed transmission) are
selected, the passage 52 is pressurized.
The shift valve 46 has an outlet passage 56 which is connected to a
friction device 58 and an exhaust passage 60 which is connected to
the control valve 54 to a pressure switch 62 and, through a flow
restriction 64, to an exhaust port 66. As is well-known with
transmission shift valves, when the governor pressure in passage 44
is sufficient to overcome the throttle pressure in passage 48, the
shift valve 46 will upshift and provide a fluid connection between
the passage 50 and passage 56 which will be effective to engage the
friction device 58. In the event that the relationship between
governor pressure and throttle pressure changes sufficiently to
permit the shift valve 46 to downshift, the passage 56 will be
connected to passage 60.
The friction device 58, shown in FIG. 1, is a conventional fluid
operated friction device operating as a clutch having a piston 68
slidably disposed in a housing 70 and a plurality of interleaved
friction plates 72 and 74 which are respectively connected to the
housing 70 and a hub 76 in a well-known manner. When passage 56 is
pressurized, the piston 68 enforces engagement of the friction
discs 72 and 74 thereby providing a friction connection between the
housing 70 and the hub 76 such that a rotary drive is provided.
The friction device 58', shown in FIG. 2, is a conventional fluid
operated friction device operating as a brake having a piston 68'
slidably disposed in a housing 70' and a plurality of interleaved
friction plates 72' and 74' which are respectively connected to the
housing 70' and a hub 76' in a well-known manner. When passage 56
is pressurized, the piston 68' enforces engagement of the friction
discs 72' and 74' thereby providing a friction connection between
the housing 70' and the hub 76' such that a stationary reaction
member is provided.
The control valve 54 includes a housing 78 having a stepped bore 79
with a large diameter 80 and a small diameter 82 in which stepped
bore 79 is slidably disposed a spool valve 84. The spool valve 84
has a large land 86 cooperating with diameter 80 and a small
diameter land 88 cooperating with diameter 82. A compression spring
90 is operative to urge the valve spool 84 rightward in bore 79 as
shown.
The fluid passage 52 is connected to the diameter 82 and is
effective to supply fluid pressure to operate on the right end of
land 88. The passage 60 is connected to the housing 78 so as to
supply fluid to the differential area 91 formed in the bore 79. An
exhaust passage 92 is also connected to the diameter 80. When the
passage 52 is pressurized, the valve spool 84 will move leftward
against spring 90 to provide an unrestricted fluid communication
between passage 60 and exhaust passage 92 in the space provided by
the differential area 91. This will occur when the operator selects
some drive ratio other than automatic drive as described above.
The passage 60 will be pressurized whenever ratio interchange
occurs within the transmission requiring the disengagement of
friction device 58. During the disengagement of friction device 58,
the volume of fluid required to maintain the piston 68 activated is
exhausted through the passage 60. The fluid pressure in passage 60
operates on the differential area 91 to move the valve spool 84 to
the left and thereby provide a controlled connection between the
passage 60 and exhaust passage 92. The differential area 91 and
spring 90 are designed such that a minimum pressure, for example,
30 psi, is maintained within the passage 60. However, the passage
60 is always in communication with exhaust through restriction 64.
Thus, when the friction device 58 is disengaged, the exhaust
pressure will be substantially instantaneously reduced to 30 psi
and will thereafter decay at a rate determined by the size of
restriction 64.
The electrical switch 62 is a conventional pressure sensitive
switch which, when activated by the fluid pressure level in passage
60, is effective to provide an electrical signal through electric
line 94 to actuate the solenoid in such a manner as to ensure that
fluid pressure is directed to passage 32 thereby disengaging the
torque converter clutch 40. The electrical switch 62 is preferably
designed to be actuated by fluid pressure of 5 psi or greater.
Thus, during the initial disengagement of friction device 58, the
fluid pressure in passage 60 will actuate the electrical switch 62
thereby causing operation of the solenoid 22 resulting in
disengagement of the torque converter clutch 40. As the fluid
pressure in passage 60 decays, the ratio interchange requested by
the transmission control will be completed and the fluid pressure
in passage 60 will approach 0 psi. When the fluid pressure in
passage 60 is below the threshhold level of electrical switch 62,
the electrical switch 62 will operate so as to cause the solenoid
22 to be activated in such a manner as to exhaust passage 32 while
pressurizing passage 30 thereby reengaging the torque converter
clutch 40.
Should the operator manually downshift the transmission, the fluid
pressure in passage 52 will operate the control valve 54 in such a
manner as to provide a substantially unrestricted flow connection
between the exhaust port 92 and passage 60 such that disengagement
of the torque converter clutch 40 will not occur at this time.
While the above control system has been described as controlling a
torque converter clutch, it will be obvious to those skilled in the
art that the system can be incorporated to provide momentary
disengagement of any friction device such as an input clutch or a
continuously engaged reaction member. It is also obvious that the
friction device 58 can be a clutch or a brake and when used with a
four-speed transmission having overdrive, such as that shown in the
above-mentioned Borman patent, the friction device would be a
brake.
Obviously, many modifications and variations of the present
invention are possible in light of the above teaching. It is
therefore to be understood that within the scope of the appended
claims, the invention may be practiced otherwise than as
specifically described.
* * * * *